Recording and storing of digital data in a memory or the like is performed on a daily basis because of the widespread use of digital cameras, computer processing and so on.
At present, information recording media such as memory chips using flash memories which are nonvolatile memories and CDRs are used for information recording and long-term storage.
In memory chips, to avoid accidental writing or the like, there are proposed various techniques for reliably storing information such as inhibiting writing after recording information (for example, refer to PTL 1 and PTL 2).